DSRC er et system for enveis eller toveis trådløs kommunikasjon med kort til medium rekkevidde,som blant annet brukes til å automatisere innkreving av bompenger i de største byene i Norge.Systemet benytter en interrogator og en DSRC-brikke populært kalt bompengebrikke. DSRCbrikkenmodulerer inn en unik identifikasjon på signalet den får fra interrogatoren, som foreksempel kan brukes til å identifisere brukeren som passerer igjennom en bompengering.NORBIT er et firma lokalisert i Trondheim som utvikler og produserer DSRC-produkter, blandtannet til det norske AutoPASS-systemet. NORBIT produserer et stort antall DSRC-brikkerhvert år, derfor er det viktig å ta hensynet til produksjonenskostnader. DSRC-brikkene kangjøres rimeligere ved bruk av andre substrat og ved å integrere komponenter som en del avgeometrien til antennen. Aluminiumsoksid er et substrat på markedet som er rimeligere, har godegenskaper for høye frekvenser, og kan fungere like godt som det substratet som brukes i dagensproduksjon. Dette substratet har høyere dielektrisitetskonstant, som fører til at antennen ogtilhørende matenettverk må redesignes.Studiet har da omhandlet hvordan antennen til DSRC-brikken kan designes med aluminiumsoksidsubstrat og fortsatt fungere like godt som antennen til dagens DSRC-brikke. I simuleringene gikkbruken av aluminiumsoksid gikk på bekostning antenneforsterkningen, men det viste seg imidlertidmulig å kompensere for denne nedgangen ved å eksitere andre og litt utradisjonelle TM-moder iantennen. Dagens DSRC-brikker bruker ortogonale spalter for å oppnå sirkulær polarisasjon, mendet viste seg også mulig i simuleringene å bruke geometrien til selve antenneelementet for å oppnådet samme.Det ble utarbeidet to forslag til antennedesign, desverre viste det seg at det var stor forskjell mellomsimulering og målinger på fysiske antenner. Testantennene tilfredsstillte ikke kravene tilundertrykkelse av krysspolarisasjon og konversjons forsterkning til en DSRC-brikke. Det er ganskevanlig at det må flere revisjoner til for å få et optimalt antennedesign. Derfor er det også forslåttvidereføring og forbedringer av antennedesignet.

This report deals with the possibility of creating a LED light source, to be used withhyperspectral fluorescence imaging. There are commercially available light sources thatcould be used, but they are expensive, they do not necessarily emit the right wavelength, the uniformity of the field is questionable and they are difficult to modify.First a batch of Light emitting diodes were acquired, these were subjected to a seriesof tests to classify their limitations and determine which diodes were to be included in the final light source. A spectrometer was used to determine the emitted wavelength of each diode and which scenarios could change the wavelength of the emitted light. Aphotodiode was used to acquire the viewing angle of the LEDs and their relative radiantpower. Images gathered by a hyperspectral camera were used to determine the relevancyof noise produced by the current source. When the light emitting diodes were chosen,the photodiode was used to make an image of the light field. The final light source wasmounted on the hyperspectral camera to gather fluorescent images.The final tests revealed a fully functional light source with potential to be used on aregular basis, but the current source was too cumbersome and the field was not optimal.These are issues that can be dealt with and this light source can in the future provide a cheap and easily modifiable light source alternative.

SammendragDenne oppgaven ser på metoder for databasert prediksjon av spredningsfaktorer. Teorien bak dette har blitt presentert. Det har blitt utarbeidet en metode for å lage måleserier med impulsresponser langs en linje i et rom. Disse måleseriene har blitt lastet inn i Matlab. Her har det har blitt utarbeidet en metode for etterbehandling av disse, med den hensikt å hente ut hver enkelt bølgefront fra den samlede matrisen med alle impulsresponsene. Dette har gjort det mulig å studere hver enkelt bølgefront i detalj og sammenligne de med simulerte verdier. Feilkilder i forbindelse med målingene og etterbehandlingen har også blitt vurdert. Det pekes til slutt på en del videre arbeid som kan være aktuellt å gjøre i framtiden for å utvikle og studere metoden enda nærmere.

This research is entirely devoted to the study and fabrication of structures with periodic dielectric constants, also known as photonic crystals (PhCs). These structures show interesting dispersion characteristics which give them a range of prohibited frequencies that are not allowed to propagate within the crystal. This property makes them suited for a wide array of photonic-based components. One-dimensional photonic crystals are already commercialized and are of widespread use in for example thin-film optics, and two-dimensional PhCs are available in the form of photonic crystal fibers.Much work is being done on the analysis of photonic crystals and their application in various photonic components. In designing any photonic crystal component the properties of the crystal must first be understood and analyzed. By using frequency-domain simulation software we have studied the properties of bulk photonic crystals and designed the ideal structure for confining light of any design wavelength within a three-dimensional photonic crystal slab.Through simulations, the ideal periodicity of the PhC has been found along with its optimal geometry for waveguiding purposes. The study was then extended to three dimensions and the optimal thickness of the PhC slab was found. By using these determined values we were able to properly confine light inside a defect in a photonic crystal structure. This phenomenon allowed us to briefly examine the use of a photonic crystal as a waveguide. This research was then continued by attempting to fabricate such a device. Methods entailing how to create a silicon-on-insulator wafer through plasma enhanced chemical vapor deposition were developed. Profilometry, refractometry and ellipsometry were used to characterize the quality of the SOI wafer. A surface roughness between 1.5-3.5 nm was found. The losses of the amorphous silicon was attempted to be measured through ellipsometry, but the ellipsometer was found incapable for loss meassurements. Better testing methods must therefore be developed.The PhC waveguiding structure is formed thorugh electron-beam lithography, and various thicknesses of photoresist are tested and characterized. Furthermore, various materials were attempted as an etch mask. Polymethyl methacrylate, $SiO_2$, and chromium were all utilized, where only the latter showed good enough selectivity for silicon etching. This lead to using both chromium and $SiO_2$ as the mask of choice. Several etching methods were tested. Both standard wet etching, room-temperature reactive ion etching recipes as well as cryogenic inductively coupled plasma reactive ion etching recipes were employed. Dry etching was found to be of insufficient quality, while the complete isotropy of wet etching rendered it impractical for fine structures needed for a PhC waveguide.The final solution which allowed the formation of the photonic crystal was a stacked structure, using both chromium, oxide, and PMMA throughout the etching process in order to achieve the wanted results. The PMMA was used as an etch mask to imprint the pattern in the oxide layer. The oxide layer was in turn used as an etch mask to imprint the pattern into the chromium, and the chromium served as the final mask to be used during cryogenic silicon etching. The cryogenic silicon etching recipe was characterized and shown to be sufficiently anisotropic as well as having a rather high maximum etch depth. The recipe show an unwanted formation of so-called silicon grass, and a high sidewall roughness is observed. Finally, a complete PhC waveguiding structure with both a grating, a taper, and a silicon waveguide is fabricated. Although they require more work to be optimized, the methods presented in this thesis provide the basis for fabricating a multitude of optical components, not only PhC's.

Today's audio in video-conference rooms do not in general have high quality audio standards.Most of the set-ups are PC-Speakers mounted on the wall, with a microphone on the table. With this, strong room modes are often excited from the speakers. When speaking to someone which also have bad equipment, the speech-intelligibility can be really bad. One solution presented with this Master thesis is to improve the loudspeaker set-up by mounting a DML(Distributed Mode Loudspeaker) above and parallel to the conference table. The DML will then radiate sound on both sides of the table equally in opposite phase, like a dipole. This will also minimize sound-radiation to the ceiling and the office-table.The DML is designed and modified from a loudspeaker originally deigned by the loudspeaker-company e-Scape. The Plexiglas panel, made out of an Acrylic material, has exciters mounted on the panel. After testing different combinations of two and three exciters in an anechoic chamber, the polar frequency response of the DML with only one exciter had a much better response than the other combinations.The idea of mounting the DML over the table is that the audience will get closer to the sound source, and room-effects will be very small compared to the direct signal. This should give a much better speech-intelligibility of the perceived sound signal compared to existing solutions. Subjective tests show that the majority of the participants preferred the DML rather than the PC-Speaker in all areas; a more natural sound, more closeness to the one speaking and better speech-intelligibility.One problem, which is seen on the measurements and feedback from the participants on the subjective test, is a low SPL(Sound Pressure Level) in the low frequency area. Under 100Hz the magnitude of the DML is reduced, compared to the response of ordinary monopole speakers. From this frequency area one can also see some dipole effects from the results, which gives us good qualities such as less radiation to the ceiling and the office table.

I små rom, kan fenomenet resonans være årsak til ugunstige akustiske forholdved at visse frekvenser blir overdrevent kraftige mens andre toner blir knapthørbare. Spesielt gjelder dette rom tiltenkt akustisk bruk, som opptaksstudioerog kontrollrom. Problemet kan unngås ved akustisk behandling i ettertid og/ellerarkitektonisk planlegging, og begge deler kan dra nytte av datasimulering. Tilgjengeligesimuleringsverktøy er konsentrert på mellom- og høyfrekvensområdet, ogdekker ikke lavfrekvente bølgers diffraktive oppførsel. Akselerasjon av parallelleberegninger på GPU tillater derimot hurtig og presis simulering, med metodeneFDTD og FDFD. En programvare beskrives og delvis utvikles i C#. Den drarnytte av GPU-en gjennom Cudafy via CUDA. Den vil forventes å kunne assistereved plassering av høyttaler, lyttepunkt og bassabsorbenter, såvel som i geometriskutforming av et rom.I denne oppgaven betraktes resonansproblemet først fra et erfaringsperspektiv,liknende situasjoner og mangelen på reelle løsninger identifiseres, og dette dannerbakgrunnen for arbeidet. Videre behandles fenomenet resonans teoretisk, i enkletermer og med flere eksempler. Dette etterfølges av en matematisk-teoretiskgjennomgang av simuleringsmetodene FDTD og FDFD. Til slutt beskrivesimplementasjonsdetaljer og utarbeidede løsninger, samt de uløste utfordringene– især FDFD-implementasjon – som gjenstår før programmet kan bli en realitet.

A prototype of a fiber based absorptionspectroscopy instrument is built. A single mode fiber pigtailDistributed Feedback laser (DFB) is used to scan a known$mbox{NH}_3$ absorption line near $1512nm$ ($6614cm^{-1}$). $2mm$diameter InGaAs PIN photodiodes are used to convert the light signalto electrical signals by use of special designed transimpedanceamplifiers. Laser modulation, coherent detection at twice themodulation frequency (second harmonic detection), other electronics,and digital signal processing are provided by Norsk Elektrooptikk.bigskip The DFB laser from NEL (NLK1S5EAAA) delivers 10mW fiberoutput and has maximum output around 30mW at maximum injectioncurrent of 200mA. This laser was found to be very quiet at dcoperation. However, in wavelength modulation spectroscopy operationit exhibit large modulation noise that was found to stem from thefiber coupling inside the laser module. A detection limit of$6times10^{-5}$ to $1times10^{-4}$ in absorbance unit with 0.712moptical path length and an effective measurement bandwidth of 52Hzwas achieved by this laser. This is significantly above thedetection limit with free air lasers which achieve $3times10^{-6}$relative absorbance (0.15ppm $mbox{NH}_3$ at room temperature andatmospheric pressure). The acquisition time for each concentrationmeasurement takes 3.2s. Hence, the response time is very fast whichis a common property of wavelength modulation spectroscopy.bigskip The modulation noise problem was attacked by an electronicnoise cancellation scheme. The idea was that since the noise sourceis inside the laser module and no external optical component can beused to reduce it. With great linearity and reliability propertiesof fused biconical taper (FBT) couplers the laser beam is split intotwo identical beams with nearly equal amount of the same noise. Onebeam, signal beam, is used to induce second harmonic signals in thegaseous path. The other beam goes directly to an identicalphotodetector and is used as a reference signal. Two specialdesigned noise canceller circuits were built to remove commonsignals. Both the circuits, based on current subtraction (notoptimized) or voltage subtraction, give comparable results. Themodulation noise was reduced by more than 12dB. A detection limit of$5times10^{-6}$ was achieved with this prototype. Even aftertransmitting the laser beam through a 3200 meter single mode fiber asignal to noise ratio (relative to 100ppm signal) of $180times$.Hence, a sensitivity is $1.1times10^{-5}$ in absorbance unit wasachieved with the basic noise canceller (not optimized). Thiscorresponds to a detection limit of 0.55ppm ammonia (12.5ppm withoutcancellation). The optimized noise canceller could reduce this by afactor of 3 or more.bigskipThe basic noise canceller based on current domain subtraction wasinvestigated in detail and optimized. This new circuit suppressedthe intensity modulation signal by more than 70dB. The 2f noise wasreduced to approximately 50ppb or $1.1times10^{-6}$ in absorbanceunit with an effective noise bandwidth of 52.3Hz and 1m optical pathlength. This is a record sensitivity with such simple electronics.The sensitivity of our fiber based prototype is limited by thefluctuating etalon fringing in the signal beam. Under normaloperation the prototype achieves approximately $pm20$ppb zero pointdrift in the concentration with an acquisition time of 48s (3.5Hznoise bandwidth). By our knowledge these results are the bestavailable and are competitive with the much more complex frequencymodulation spectroscopy technique.bigskipThese balanced transimpedance amplifiers also have the ability tomeasure the absorption spectra directly without modulation.Determining the absorption linewidth and its shape is now a straightforward task. By use of dual beam configuration and noisecancellation thermal effects that caused background fluctuationswere greatly suppressed. The laser delivers high intensity light,$sim22mW$. The dominating noise is the photocurrent shot noise andthe etalon fringing from optical components in the signal path.Remote sensing, in-situ, noninvasive measurements can be performedwith this instrument. In some cases it's flexibility, and remotesensing possibility are of great attractiveness for the industry.The sensitivity is also improved by a factor of two with the fiberbased tuneable diode laser absorption spectroscopy instrument.bigskipIn the end of this thesis we demonstrate the ability to measuremultiple absorption lines simultaneously. The number of measurementpaths is limited by the laser output power.

Characterize silicon wafers used in solar cell production with a NIR-LCI interferometer. The interferometer is further developed and measurements on silicon samples are carried out.

In this project, the growth parameters of Pulsed Laser Deposition are optimized in order to obtain a high quality interface between two complex oxides, LaAlO3 and SrTiO3. The prepared samples are compared by their sheet resistance, and the influence by the various growth parameters are investigated.The main finding is that reducing the laser fluence significantly lowers the sheetresistance. The lowest obtained sheet resistance was 81.2kohm. This value wasobtained with a laser fluence of 0.7 J/cm^2 and the results indicate that morecan be gained by going even lower. In previous work, a strong anisotropy of the sheet resistance has been observed. The anisotropy is further studied in this project and compared with the step-and-terrace topography at the interface. Atomic Force Microscopy is used to obtain the step directions and terrace widths, and these values are compared with resistance measurements. No correlation is found between these data. The results suggests that the anisotropy is due to other factors than the steps-and-terraces.

In this thesis, methodology for partial self-reconfiguration of synchronous modules has been developed. A simple software-based scheduler has been built for scheduling synchronous modules on the FPGA. The motivation behind this was that partial reconfiguration of synchronous modules at run-time had not been performed earlier in the AHEAD-project. Also, the project report written by the same author as this thesis has shown that a synchronous module can be replaced in a bitfile. However, the project report did not perform this reconfiguration at run-time.Based on the project report, the problem has been decomposed and simple tests using clocked flip-flop designs have been performed on the FPGA. These tests forms a proof-of-concept for partial self-reconfiguration of synchronous modules on the Virtex-4 FPGA. However, the tests also showed that the reconfiguration time was quite high. It took several seconds to write one partial bitstream to the configuration memory.Vegard Endresen has previously made a backend module for data transfer between the HWOS and a reconfigurable module. Experiments were performed in this thesis to see if the clocking methodology could be integrated into this backend module. The module could be built with the methodology, but a running solution on the FPGA was not shown.The software part of the HWOS was rewritten from scratch as the previous version was not thoroughly analyzed. A round-robin scheduler using priority queues has been implemented. A test-driven development technique has been used for development, hopefully making the system more robust. The scheduler is a part of a daemon running on the embedded system, where a message server handles requests for new processes and a placer places new tasks on the FPGA. The complete system was initially based on ideas and code developed by Sverre Hamre and Vegard Endresen in previous AHEAD-projects.